1 | /* glpdmp.c (dynamic memory pool) */ |
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2 | |
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3 | /*********************************************************************** |
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4 | * This code is part of GLPK (GNU Linear Programming Kit). |
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5 | * |
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6 | * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, |
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7 | * 2009, 2010 Andrew Makhorin, Department for Applied Informatics, |
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8 | * Moscow Aviation Institute, Moscow, Russia. All rights reserved. |
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9 | * E-mail: <mao@gnu.org>. |
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10 | * |
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11 | * GLPK is free software: you can redistribute it and/or modify it |
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12 | * under the terms of the GNU General Public License as published by |
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13 | * the Free Software Foundation, either version 3 of the License, or |
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14 | * (at your option) any later version. |
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15 | * |
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16 | * GLPK is distributed in the hope that it will be useful, but WITHOUT |
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17 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
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18 | * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public |
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19 | * License for more details. |
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20 | * |
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21 | * You should have received a copy of the GNU General Public License |
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22 | * along with GLPK. If not, see <http://www.gnu.org/licenses/>. |
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23 | ***********************************************************************/ |
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24 | |
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25 | #include "glpdmp.h" |
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26 | |
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27 | #if 1 /* 29/VIII-2008 */ |
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28 | /* some processors need data to be properly aligned; the macro |
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29 | align_datasize enlarges the specified size of a data item to provide |
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30 | a proper alignment of immediately following data */ |
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31 | |
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32 | #define align_datasize(size) ((((size) + 7) / 8) * 8) |
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33 | /* 8 bytes is sufficient in both 32- and 64-bit environments */ |
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34 | #endif |
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35 | |
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36 | #ifdef GLP_DEBUG |
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37 | struct info |
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38 | { DMP *pool; |
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39 | int size; |
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40 | }; |
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41 | #endif |
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42 | |
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43 | /*********************************************************************** |
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44 | * NAME |
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45 | * |
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46 | * dmp_create_pool - create dynamic memory pool |
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47 | * |
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48 | * SYNOPSIS |
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49 | * |
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50 | * #include "glpdmp.h" |
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51 | * DMP *dmp_create_pool(void); |
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52 | * |
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53 | * DESCRIPTION |
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54 | * |
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55 | * The routine dmp_create_pool creates a dynamic memory pool. |
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56 | * |
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57 | * RETURNS |
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58 | * |
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59 | * The routine returns a pointer to the memory pool created. */ |
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60 | |
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61 | DMP *dmp_create_pool(void) |
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62 | { DMP *pool; |
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63 | int k; |
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64 | #ifdef GLP_DEBUG |
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65 | xprintf("dmp_create_pool: warning: debug mode enabled\n"); |
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66 | #endif |
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67 | pool = xmalloc(sizeof(DMP)); |
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68 | #if 0 |
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69 | pool->size = 0; |
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70 | #endif |
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71 | for (k = 0; k <= 31; k++) pool->avail[k] = NULL; |
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72 | pool->block = NULL; |
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73 | pool->used = DMP_BLK_SIZE; |
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74 | pool->count.lo = pool->count.hi = 0; |
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75 | return pool; |
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76 | } |
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77 | |
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78 | /*********************************************************************** |
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79 | * NAME |
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80 | * |
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81 | * dmp_get_atom - get free atom from dynamic memory pool |
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82 | * |
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83 | * SYNOPSIS |
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84 | * |
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85 | * #include "glpdmp.h" |
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86 | * void *dmp_get_atom(DMP *pool, int size); |
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87 | * |
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88 | * DESCRIPTION |
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89 | * |
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90 | * The routine dmp_get_atom obtains a free atom (memory block) from the |
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91 | * specified memory pool. |
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92 | * |
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93 | * The parameter size is the atom size, in bytes, 1 <= size <= 256. |
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94 | * |
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95 | * Note that the free atom contains arbitrary data, not binary zeros. |
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96 | * |
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97 | * RETURNS |
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98 | * |
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99 | * The routine returns a pointer to the free atom obtained. */ |
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100 | |
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101 | void *dmp_get_atom(DMP *pool, int size) |
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102 | { void *atom; |
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103 | int k; |
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104 | #ifdef GLP_DEBUG |
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105 | int orig_size = size; |
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106 | #endif |
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107 | if (!(1 <= size && size <= 256)) |
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108 | xerror("dmp_get_atom: size = %d; invalid atom size\n", size); |
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109 | #if 0 |
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110 | if (!(pool->size == 0 || pool->size == size)) |
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111 | xerror("dmp_get_atom: size = %d; wrong atom size\n", size); |
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112 | #endif |
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113 | /* adjust the size to provide the proper data alignment */ |
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114 | size = align_datasize(size); |
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115 | #ifdef GLP_DEBUG |
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116 | size += align_datasize(sizeof(struct info)); |
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117 | #endif |
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118 | /* adjust the size to make it multiple of 8 bytes, if needed */ |
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119 | size = ((size + 7) / 8) * 8; |
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120 | /* determine the corresponding list of free cells */ |
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121 | k = size / 8 - 1; |
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122 | xassert(0 <= k && k <= 31); |
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123 | /* obtain a free atom */ |
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124 | if (pool->avail[k] == NULL) |
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125 | { /* the list of free cells is empty */ |
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126 | if (pool->used + size > DMP_BLK_SIZE) |
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127 | { /* allocate a new memory block */ |
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128 | void *block = xmalloc(DMP_BLK_SIZE); |
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129 | *(void **)block = pool->block; |
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130 | pool->block = block; |
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131 | pool->used = align_datasize(sizeof(void *)); |
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132 | } |
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133 | /* place the atom in the current memory block */ |
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134 | atom = (char *)pool->block + pool->used; |
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135 | pool->used += size; |
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136 | } |
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137 | else |
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138 | { /* obtain the atom from the list of free cells */ |
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139 | atom = pool->avail[k]; |
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140 | pool->avail[k] = *(void **)atom; |
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141 | } |
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142 | memset(atom, '?', size); |
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143 | /* increase the number of atoms which are currently in use */ |
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144 | pool->count.lo++; |
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145 | if (pool->count.lo == 0) pool->count.hi++; |
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146 | #ifdef GLP_DEBUG |
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147 | ((struct info *)atom)->pool = pool; |
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148 | ((struct info *)atom)->size = orig_size; |
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149 | atom = (char *)atom + align_datasize(sizeof(struct info)); |
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150 | #endif |
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151 | return atom; |
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152 | } |
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153 | |
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154 | /*********************************************************************** |
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155 | * NAME |
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156 | * |
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157 | * dmp_free_atom - return atom to dynamic memory pool |
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158 | * |
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159 | * SYNOPSIS |
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160 | * |
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161 | * #include "glpdmp.h" |
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162 | * void dmp_free_atom(DMP *pool, void *atom, int size); |
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163 | * |
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164 | * DESCRIPTION |
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165 | * |
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166 | * The routine dmp_free_atom returns the specified atom (memory block) |
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167 | * to the specified memory pool, making it free. |
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168 | * |
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169 | * The parameter size is the atom size, in bytes, 1 <= size <= 256. |
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170 | * |
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171 | * Note that the atom can be returned only to the pool, from which it |
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172 | * was obtained, and its size must be exactly the same as on obtaining |
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173 | * it from the pool. */ |
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174 | |
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175 | void dmp_free_atom(DMP *pool, void *atom, int size) |
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176 | { int k; |
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177 | if (!(1 <= size && size <= 256)) |
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178 | xerror("dmp_free_atom: size = %d; invalid atom size\n", size); |
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179 | #if 0 |
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180 | if (!(pool->size == 0 || pool->size == size)) |
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181 | xerror("dmp_free_atom: size = %d; wrong atom size\n", size); |
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182 | #endif |
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183 | if (pool->count.lo == 0 && pool->count.hi == 0) |
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184 | xerror("dmp_free_atom: pool allocation error\n"); |
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185 | #ifdef GLP_DEBUG |
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186 | atom = (char *)atom - align_datasize(sizeof(struct info)); |
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187 | xassert(((struct info *)atom)->pool == pool); |
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188 | xassert(((struct info *)atom)->size == size); |
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189 | #endif |
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190 | /* adjust the size to provide the proper data alignment */ |
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191 | size = align_datasize(size); |
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192 | #ifdef GLP_DEBUG |
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193 | size += align_datasize(sizeof(struct info)); |
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194 | #endif |
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195 | /* adjust the size to make it multiple of 8 bytes, if needed */ |
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196 | size = ((size + 7) / 8) * 8; |
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197 | /* determine the corresponding list of free cells */ |
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198 | k = size / 8 - 1; |
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199 | xassert(0 <= k && k <= 31); |
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200 | /* return the atom to the list of free cells */ |
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201 | *(void **)atom = pool->avail[k]; |
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202 | pool->avail[k] = atom; |
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203 | /* decrease the number of atoms which are currently in use */ |
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204 | pool->count.lo--; |
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205 | if (pool->count.lo == 0xFFFFFFFF) pool->count.hi--; |
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206 | return; |
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207 | } |
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208 | |
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209 | /*********************************************************************** |
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210 | * NAME |
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211 | * |
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212 | * dmp_in_use - determine how many atoms are still in use |
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213 | * |
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214 | * SYNOPSIS |
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215 | * |
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216 | * #include "glpdmp.h" |
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217 | * glp_long dmp_in_use(DMP *pool); |
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218 | * |
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219 | * DESCRIPTION |
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220 | * |
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221 | * The routine dmp_in_use determines how many atoms allocated from the |
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222 | * specified memory pool with the routine dmp_get_atom are still in use, |
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223 | * i.e. not returned to the pool with the routine dmp_free_atom. |
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224 | * |
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225 | * RETURNS |
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226 | * |
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227 | * The routine returns the number of atoms which are still in use. */ |
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228 | |
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229 | glp_long dmp_in_use(DMP *pool) |
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230 | { return |
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231 | pool->count; |
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232 | } |
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233 | |
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234 | /*********************************************************************** |
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235 | * NAME |
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236 | * |
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237 | * dmp_delete_pool - delete dynamic memory pool |
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238 | * |
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239 | * SYNOPSIS |
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240 | * |
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241 | * #include "glpdmp.h" |
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242 | * void dmp_delete_pool(DMP *pool); |
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243 | * |
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244 | * DESCRIPTION |
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245 | * |
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246 | * The routine dmp_delete_pool deletes the specified dynamic memory |
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247 | * pool and frees all the memory allocated to this object. */ |
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248 | |
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249 | void dmp_delete_pool(DMP *pool) |
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250 | { while (pool->block != NULL) |
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251 | { void *block = pool->block; |
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252 | pool->block = *(void **)block; |
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253 | xfree(block); |
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254 | } |
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255 | xfree(pool); |
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256 | return; |
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257 | } |
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258 | |
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259 | /* eof */ |
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